Apparatus for forming a continuous concrete conduit



May 23, 1933. J. J. PROWANT APPARATUS FOR FORMING A CONTINUOUS CONCRETE CONDUIT Filed Nov. 9, 1951 4 Sheets-Sheet l q 5; i lll May 23, 19333.

J. J, PROWANT APPARATUS FOR FORMING A CONTINUOUS CONCRETE CONDUIT Filed Nov. 9, 1931 4 Sheets-Sheet 2 i'o's May 23, 1933.

J. J. PROWANT APPARATUS FOR FORMING A CONTINUOUS CONCRETE CONDUIT Filed Nov. 9, 1931 4 Sheets-Sheet 5 m'mw nu 11g MIL mill 7 May 23, 1933- J. ,1. PROWANT APPARATUS FOR FORMING A CONTINUOUS CONCRETE CONDUIT Filed Nov. 9, 1931 4 Sheets-Sheet 4 Patented May 23, 1933 UNETD STATES Price JOHN J. PROWAN'I, OF CHADWIGK, ILLINOIS Application filed November 9, 1931. Serial No. 573,969.

This invention relates to a method of and apparatus for the continuous molding of a structure having a duct therein and has particular reference to a concrete conduit. This invention has been perfected to accomplish the construction in place of a continuous solid concrete conduit, as distinguished from one consisting of a series of short sections of cured concrete.

The invention contemplates an improved means for holding the core which makes the duct within the conduit and also an improved anchoring means for holding the peculiarly constructed outside form which gives the conduit the proper shape. Another important feature of my invention is the shape and structure of the collapsible core which forms the cavity within the conduit.

The invention will be best understood from a consideration of the following detail description taken in connection with the accompanying drawings forming part of this specification.

In the drawings:

Figure 1 is a plan view of the invention in form to mold a conduit.

Figure 2 is a vertical section on line 22 of Figure 1, showing the position of the anchoring means for the core and outside shell.

Figure 3 is a view on line 33 of Figure 1, showing the core removed.

Figure 4 is an enlargement of the structure shown in Figure 2 for holding the core in position so that it will be in the proper position to receive the plastic material which forms the conduit.

Figure 5 shows an enlarged bracket like that shown in Figure 3 for bracing the anchoring means for the several conduit mold 49 ing members.

Figure 6 is an enlarged showing of the operating means for controlling the doors of the core.

Figure 7 is a perspective view of the larger folding door of the core with. its operating mechanism.

Figure 8 is a vertical section through a core section.

Figure 9 is a horizontal section through a core section.

showing the means formed within the conduit, on which the core rests while being extracted, after the conduit has been formed.

In Figures 2 and 3, 1 is a ditch having a rounded bottom 2, and horizontal supporting shelves 3-3 connecting the vertical walls of the ditch with the rounded bottom. It is to be noted that the rounded bottom of the ditch acts as a mold for part of the conduit and the contour of the ditch governs the shape-of that portion of the conduit P. On the supporting walls of the ditch 33 are the bed rails H which run parallel the entire length of the ditch in whlch the continuous conduit is to be formed. These bed rails are preferably pieces of wood 2 X 8, laid so that their greater surface is on the top and bottom. Attached to the bed rails H by nails 5 are the L shaped pieces 6 having complementary holes 7 to receive the pins 8 (see Figure 1). The pins 8 are encircled by the turned up edges 9 of the brace and support members 10 and 10 As stated before, the shape of the outer bottom of the conduit is governed by the shape of the bottom of the ditch and the outer upper shape of the conduit is governed by the detachable members 11 and 11 both of which have upturned edges 11*, between which the mixture is fed to form the conduit P. These two detachable members 11 and 11 are held in place to form a perfect semicircle by the brace and support straps 10 and 10. The strap 10 is longer than the strap 10, as it covers the space left vacant by the shaping members 11 and 11 The upper edge of the strap member 10 overlaps the lower edge of the strap 10 thus forming a oint which, in connection with the holding means to be mentioned later, strengthens the upper shell. Attached to the strap 10 on the shaping member 11 by a rivet or some other suitable means is the hinge base 12. Hinged to this base by the hinge pin 13 is the strap member 14. The strap member 14 extends over the space between the shaping members 11 and 11 through cutout spaces 13 in the upright portions 11 of the shaping members 11 and 11. The outer end of the strap 14 has a hole therein through which penetrates the open projection 14, which is attached to the strap 10. The strap 14 is held down on the strap 1O by a V shaped wedge 15. The above represents the locking means for holding the two forming sections 11 and 11 in spaced relation to each other so that the two members form a semi-circle in which is molded the upper half of the conduit.

After the rail beds 44 have been laid on the previously prepared shoulders 33, cleats 16 are driven into the solid earth over the rail beds so that the same will not have vertical movement out of the ditch. The cleats 16 have formed thereon projections 17 into which fit the toes 18 of the L shaped members 19, (see Figures 3 and 5). Riveted or bolted to the L shaped members 19 are the extensions 20 which, in connection with the L shaped members 19 form a support over the conduit molding structure and prevent the same from having any lateral movement. The L shaped members 19 with their corresponding portion 20 are held in contact with each other by means of brackets 21 which are made of two straps of metal riveted at 22 to the L shaped members 19. Through bolts 23 the straps forming the brackets are brought together to clamp the members 20. By the above assembly a frame is made and positioned over the conduit forming apparatus which holds the bed rails 4-4 so that they are kept parallel to each other with the structure supported thereon. This overhead structure also prevents the cleats 16 carried at the bottom thereof from coming out of the hard earth in which they have been driven.

The cylindrical collapsible core A is made from a sheet of metal and has a drawn end 24, (see Figures 8 and 9), which forms a stove pipe fit with the adjacent end of another section of the core. In one side of the core and running parallel therewith are hinged sections of the core which will be hereinafter referred to as the large door 25 and the small door 26. These doors are hinged to the core of which they form a part, by the hinge pins 27 and 28. Parallel with the hinges that hold the large and small doors of the core and on the inner side of the core are riveted the L irons 29 to give strength to the core. There are also other L irons 30 which run laterally of the core and are attached to the core to give it strength. In each section of the core adjacent the ends thereof, are two curved fiat pieces 31, of spring metal, which tend to collapse the core when the positive expanding means has been withdrawn. Running longitudinally of the core is the draw rod 32 which is used to eX- pand and contract the core and to open and close the doors of the core when the same is placed in the shell or withdrawn. On the draw rod 32 at each end thereof is a cam 33 having the shape of a frustum of a pyramid, on which ride the rollers 34 for closing and opening the core. The rollers 34 are mounted on arms 35 that are connected to the longitudinal L irons 30 that run parallel with the core. Attached for pivotal movement to the arm 35 adjacent the rollers 34 is a link 36 connected to the draw rod 32 through the butterfly 37. On the end of the draw rod 32 adjacent the end of the core which has the contracted bead 24 is a collar 38 having holes therein to receive the links 39, which connect the longitudinal bracing members 29 and 30 with the collar. Through this mechanism, eifort exerted to pull the core out of the conduit is spent without injury to the mechanism for collapsing the core and folding the doors of the core.

In each section of the core midway between its ends on the draw rod 32 is permanently aflixed a pin 40. On the pin 40 is mounted, for pivotal movement the lever 41 which is permanently attached to one of the longitudinal L irons 30 by a rivet 42. To the short end of the lever 41, a link 43 is attached by a joint 44 adapted to have also pivotal movement, (see Figures 6, 7 and 8). On the bottom of the large door 25 is formed a loop 45 into which is mounted the L shaped link 46 connected to the previously described lever 43. At the other end of the L shaped member 46 is a connecting link 47, which in turn is connected to one of the arms 35 by a connection 48 which has a pivotal movement. Oonnected to the under side of the smaller door 26 is an arm 49 to which is attached a coil spring 50, the other end of the spring is hooked into the hole 51 formed in one of the longitudinal stay members 30. The function of this spring is to tend to close the door except when the same is positively pushed open by the mechanism previously described. Welded or attached by other means to the lower side of the large door 25 are projections 52 on which the smaller door rests. This rest or stop positions and guides the doors so that they close together in unison.

The several core sections are connected together by chains 53, in which are hooks or snaps 54 that enter the eyelets 55 in each end of the draw rods 32. There is sufficient chain so that when the sections are expanded and abutting each other in place there is slack within the chain 53.

The lower end of the members 10 and 10 (see Figures 1 and 2) where the same are attached to the bed rails 4-4, are cut away as at 56 and through these openings is inserted the metal pins 57 which penetrate through the bed rails 44 and hold the same with the structure supported thereby to the trench.

After the bed rails 4 have been placed in position, the metal pins 57 are driven through holes in the bed rails 44 until the metal pins penetrate down in the supporting shelves 3-3 of the trench. Previously, wire 58 having loops 59 thereon, through which the metal pin 57 penetrates, has been threaded through the bed rail 44 so as to form the upper wire positioning device for the core of the moulding device (see Figures 2 and 4). The wire 60 having loops 61, is then placed over the pin 57 and down under the core and the other loop 61 is then p aced on top of the pin 57, directly opposite on the other bed rail. The two wires 58 and 60 form positioning means for the core and thus the position of the cavity to be formed in the conduit by the core.

The means for opening and closing the collapsible core is the draw rod 32 carrying on it the cams 33 which expand the collapsible core when the roller attached to members extending to the outside of the core ride over to the larger part of the cam. The door opening and closing mechanism raises and lowers the doors to fill in the longitudinal space between the edges of the core when the same is expanded, is also controlled by the position of the draw rod. The mechanism for opening or closing the doors, is the lever 41 which is moved backward as shown in Figure 8, when the draw rod is pulled so that the rollers 34 of the expanding mechanism are not en gaged by the inclined cam surfaces.

Upon the supporting wires 60, which form a cradle for the core and position it relative to the bottom of the ditch and the core A, are placed two longitudinal wires 63 (see Figures 2, 3 and 14) that have offsets therein 65, around which is bent the head of the pin 64. he pin is pointel and is driven into the hard ground at the bottom of the ditch. These two wires 63 are in the space into which concrete is subsequently placed and when the conduit is finished, they are in the inside bottom of the conduit supporting the core. They form a trackway on which the core is withdrawn when the conduit or pipe has been molded and has set.

Attention is directed to the fact that the collapsible core collapses one end at a time although the means for holding each section of the core expanded are withdrawn at the same time. This is because one end of the core engaged over the beveled section 24 of the adjacent core (see Figures 8, 9 and 10), and cannot contract even though the rollers 34 are not engaged by the cam 33. Vhen one section of the core has been collapsed and the two doors folded in by pulling on the draw rod 32, one end of the section affected will collapse assisted by the springs 31, while the other end of the section will not collapse until the first section has been withdrawn from the second section so that the beveled stove pipe connection 24 has been broken. A further pull on the draw rod will take up the slack in the connecting chain 53 which, on a further pull, a

for the next sect-ion, that is to say, remove the cam surface out of contact with the rollers 34. By the above operation, each section or core is completely collapsed before another core is unlocked, which means that only one core at a time will engage the conduit when it is attempted to withdraw them from the formed conduit and furthermore there is no burden on the frame of any core by reason of the pull on the drawbar. To keep the core sections from turning, while being withdrawn from the finished conduit, I prefer to Weight the bottom of them by making the angle iron 30 at the bottom heavier than the rest, or by placing a small metal bar in the bottom of the core adjacent to that angle iron.

Referring again to Figures 2 and 3, a filler strip 6:2 is laid over tne doors of the core so that concrete will not enter the door construction and retard the opening of the doors when the core is to be withdrawn from the conduit. This strip 62 remains in the conduit, and forms a reinforcement for it like the wires 58, 60 and which are left in the finished conduit by cutting the loops of the same from the pin 57 when the mold structure is taken up from the finished conduit.

As stated before, the core sections pene trate each other where they come in contact while the individual shell members only abut each other. And further when successive cores are in place the interior adjacent ends of the drawbars are contacted 55, (Fig. 13), while the other ends of the first and last drawbars are abutted, thus assuring greater stability to the co-related structure.

What I claim is 1. In apparatus for nolding a continuous concrete conduit in a trench, an expansible core having a contracted end and comprising a longitudinally split cylindrical band of sheet" metal, opposite inwardly opening hinged doors within said split, and means for controlling the opening and closing of the doors and to contract and expand the band comprising a draw bar having a substantially frusto conical cam thereon, arms carried by the band terminating in rollers that bear upon the cam, links pivoted to the arms and to the draw bar for moving the cam between the rollers, a lever pivoted to the band and pivoted intermediate the ends to the draw bar, lever mechanism operatively connected to the free end of the last named will release the lockin means" lever and to the free edges of the doors for moving the doors upon movement of said lever, and a lever pivoted to one of said arms and to said leverv mechanism adapted to be moved longitudinally of the core when the draw rod is actuated and coact with the first named lever in moving the doors.

2. In apparatus for molding a continuous conduitin a trench, an expansible core, an outer arched shell having an opening therein to permit cement being poured between the shell and the core, bed rails adapted to be affixed to the side walls of the trench, an overhead brace structure attached to the bed rails and preventing the bed rails from moving vertically out of the trench or laterally towards each other, wire loops engaged above and below the core and secured to said bed rails for anchoring the core centrally within the shell, means for anchoring the lower portions of the shell to the bed rails, and means for contracting the core radially within the shell.

3. Apparatus for forming a continuous concrete conduit in a trench comprising longitudinal bed rails adapted to be secured on shelves of the side walls of the trench in which the conduit is to be formed, an overhead frame secured to the bed rails and adapted to prevent dislodgment thereof, a sectional collapsible core between the rails adapted to form the duct within the conduit, a sectional outer shell secured to the bed rails adapted to shape the upper outside of the conduit, wire loops trained over the top and bottom of the core and terminally connected to the bed rails to maintain the core centralized within the shell, said shell having the lower portions thereof extending upon the bed rails, pins removably securing said portions to said rails, and means for expanding and contracting the sectional core relative to the arched shell.

4. In apparatus for molding a continuous conduit, an expansible core composed of a band of sheet metal having a longitudinal split therein, inwardly opening hinged doors closing said split, and means for expanding the band and simultaneously operating said doors comprising a draw bar disposed axially within the band, a cam surface on the draw bar having the shape of a frustum of a cone, arms carried by the band and having rollers at the inner ends bearing upon said cam surface for expanding and contracting the band when the draw bar is moved, a lever pivoted to the band and to the draw bar and having a free end terminating near the meeting edges of the doors, a lever pivoted to one of said arms and extending towards the free end of the first named lever, and means operatively connecting the free ends of both of said levers with the meeting edges of the doors for swinging the doors when said draw bar is moved longitudinally of the core.

5. In apparatus for molding a continuous conduit in a trench, a shell for shaping the outer upper portion of the conduit, parallel bed rails outside of the lower side portions of the shell, means for securmg said portions of the shell to said bed rails, said shell being composed of members which form a substantially semi-circular cover over the top of the conduit, a collapsible core inside of said shell,

and means for securing said core to said bed for securing said shell sections to said rails,-

means for securing said core sections to said rails concentric with said shell sections, draw bars longitudinally movable in the core sections, means operatively connecting the draw bars with the core sections for contracting the same, and slack chains connecting the ends of adjacent draw bars for actuating the draw bars so that movement of one draw bar will not affect the position of the next adjacent draw bar until the first mentioned draw bar has been moved a distance from the last mentioned draw bar.

7. In apparatus for molding a continuous conduit, a sheet metal. collapsible core, a draw bar in the center of the core, cam blocks on the draw bar, longitudinal L-irons forming a frame within the core, arms secured to said irons and having terminal rollers resting on the cam blocks, links pivotally connected to the arms and to the draw bar for moving the cam between the rollers, doors carried by the core and opening inwardly toward the draw bar, a door control lever pivoted to said L-iron at the bottom of the core and pivoted to the draw bar, the upper end of the member terminating at said doors, an operative connection between said upper end of the lever and one of the doors, the other door operatively engaging and being controlled by movement of the first named door, a lever operatively connecting one of said arms with the operative connection between the first named lever and said door, the core being beveled at the forward end to engage the next adjacent core in a stovepipe joint, a-collar on the forward end of the cam block, and links connecting said L-irons with said. collar and being adapted to receive the pull upon the draw bar and prevent injury to the various parts of the device.

In testimony whereof, I affix my signature.

JOHN J. PROIVANT. 

